Photochromic substituted naphthopyran compounds

ABSTRACT

Described are novel reversible photochromic 3H-naphtho[2,1-b]pyran compounds, of the following graphic formula:   &lt;IMAGE&gt;   wherein R1 is hydrogen or alkyl, R2 is hydrogen or preferably a carboalkoxy group and R3 is hydrogen or preferably an alkyl group, provided that either R1 or R2 is hydrogen, and B and B&#39; are the aryl groups phenyl or naphthyl, a heterocyclic aromatic group or together form a spiro adamantylene group. Also described are organic host materials that contain or that are coated with such compounds. Articles such as ophthalmic lenses or other plastic transparencies that incorporate the novel naphthopyran compounds or combinations thereof with complementary photochromic compounds, e.g., spiro(oxazine) type compounds, are also described.

DESCRIPTION OF THE INVENTION

The present invention relates to certain novel naphthopyran compounds.More particularly, this invention relates to novel photochromicnaphthopyran compounds and to compositions and articles containing suchnovel naphthopyran compounds. When exposed to light radiation involvingultraviolet rays, such as the ultraviolet radiation in sunlight or thelight of a mercury lamp, many photochromic compounds exhibit areversible change in color. When the ultraviolet radiation isdiscontinued, such a photochromic compound will return to its originalcolor or colorless state.

Various classes of photochromic compounds have been synthesized andsuggested for use in applications in which a sunlight-induced reversiblecolor change or darkening is desired. U.S. Pat. No. 3,567,605 (Becker)describes a series of pyran derivatives, including certain benzopyransand naphthopyrans. These compounds are described as derivatives ofchromene and are reported to undergo a color change, e.g., fromcolorless to yellow-orange, on irradiation by ultraviolet light attemperatures below about -30° C. Irradiation of these compounds withvisible light or upon raising the temperature to above about 0° C. isreported to reverse the coloration to a colorless state.

The present invention relates to novel 3H-naphtho[2,1-b]pyran compoundshaving certain substituents at the number 8 carbon atom and certainsubstituents either at the number 7 or number 9 carbon atom of thenaphthopyran. These compounds have been found to have an improved solarresponse and an unexpectedly higher activating wavelength thancorresponding compounds having no substituents on the naphtho portion ofthe naphthopyran or a substituent at the number 8 carbon atom. Asdiscussed later, the number 7, 8 and 9 carbon atoms of3H-naphtho[2,1-b]pyran compounds are part of the naphtho portion of thenaphthopyran.

DETAILED DESCRIPTION OF THE INVENTION

In recent years, photochromic plastic materials, particularly plasticmaterials for optical applications, have been the subject ofconsiderable attention. In particular, photochromic ophthalmic plasticlenses have been investigated because of the weight advantage theyoffer, vis-a-vis, glass lenses. Moreover, photochromic transparenciesfor vehicles, such as cars and airplanes, have been of interest becauseof the potential safety features that such transparencies offer.

Photochromic compounds useful in optical applications, such asconventional ophthalmic lenses, are those which possess (a) a highquantum efficiency for coloring in the near ultraviolet, (b) a lowquantum yield for bleaching with white light, and (c) a relatively fastthermal fade at ambient temperature but not so rapid a thermal fade ratethat the combination of white light bleaching and thermal fade preventcoloring by the ultraviolet component of strong sunlight. In addition,the aforesaid properties are desirably retained in conventional rigidsynthetic plastic materials customarily used for ophthalmic and planolenses when such materials have applied to or incorporated therein suchphotochromic compounds.

Another factor regarding the selection of potential photochromiccompounds for optical applications is their response under a variety ofsolar conditions, e.g., a full mid-day sun, or the more highly filteredsolar rays found early or late in the day. Ideally, photochromiccompounds respond equally well under these differing conditions. Such avariety of solar conditions can be simulated on an optical bench with aXenon lamp fitted with either a 320 nanometer or a 360 nanometer cutofffilter. Preferred photochromic compounds are those that have a minimaldifference in optical density after exposure to both wavelength rangesof ultraviolet light. The ultraviolet light having a wavelength higherthan 360 nanometer represents low light conditions that occur early orlate in the day when the shorter wavelength components of the UVspectrum are attenuated.

In accordance with the present invention, it has been discovered thatcertain novel 3H-naphtho[2,1-b]pyran compounds having a high quantumefficiency for coloring in the near ultraviolet and an acceptable rateof fade may be prepared. These compounds also have improved solarresponse levels as compared to other substituted and unsubstitutednaphthopyran compounds. This attribute resolves a problem that has beenfound with other photochromic compounds of reduced photochromic responsein low light conditions that occur early or late in the day.

The compounds of the present invention may be described as3H-naphtho[2,1-b]pyrans that are substituted with an oxy-bearingsubstituent at the number 8 carbon atom and with either an alkyl groupat the number 7 carbon atom or with a carbonyl bearing substituent atthe number 9 carbon atom. These naphthopyran compounds may berepresented by the following graphic formula: ##STR2## In graphicformula I A, R₁ may be hydrogen or a C₁ -C₆ alkyl, e.g., methyl, ethyl,propyl, n-butyl, iso-butyl, n-amyl, iso-amyl, hexyl, etc. Preferably, R₁is hydrogen or C₁ -C₃ alkyl, e.g., methyl. R₂ may be hydrogen or thegroup, -C(O)W, W being -OR₄ or -N(RS)R₆, wherein R₄ may be hydrogen,allyl, C₁ -C₆ alkyl, e.g., methyl, ethyl, propyl, isopropyl, n-butyl,iso-butyl, sec-butyl, amyl, hexyl, etc., phenyl, C₁ -C₆ monoalkylsubstituted phenyl, e.g., tolyl, cumenyl, etc., C₁ -C₆ monoalkoxysubstituted phenyl, e.g., anisyl, ethoxyphenyl, etc., phenyl(C₁-C₃)alkyl, e.g., benzyl, phenethyl, 3-phenylpropyl, etc., C₁ -C₆monoalkyl substituted phenyl-(C₁ -C₃)alkyl, C₁ -C₆ monoalkoxysubstituted phenyl(C₁ -C₃)alkyl, C₁ -C₆ alkoxy(C₂ -C₄)alkyl, or C₁ -C₆monohaloalkyl, and wherein R₅ and R₆ each may be selected from the groupconsisting of hydrogen, C₁ -C₆ alkyl, C₅ -C₇ cycloalkyl, phenyl andmono- or di-substituted phenyl, or R₅ and R₆ together with the attachednitrogen atom form an indolinyl group, or a mono- or di-substituted orunsubstituted, non-aromatic, saturated, or unsaturated heterocyclic ringcontaining from 5 to 6 ring atoms, which ring includes as the heteroatom said nitrogen atom alone or one additional hetero atom of nitrogenor oxygen, e.g., morpholino, piperidino, 1-pyrrolidyl, 1-pyrrolinyl,1-imidazolidyl, 2-imidazolin-1-yl, 2-pyrazolidyl, 1-piperazinyl, etc.,said phenyl and heterocyclic ring substituents being selected from C₁-C₆ alkyl and C₁ -C₆ alkoxy, said halo substituent being chloro orfluoro. Preferably, R₂ is hydrogen or the group, -C(O)W, W being -OR₄,and wherein R₄ is a C₁ -C₃ alkyl or allyl. In graphic formula I A,either R₁ or R₂ is hydrogen.

R₃ in graphic formula I A may be hydrogen, C₁ -C₆ alkyl, phenyl(C₁-C₃)alkyl, C₁ -C₆ monoalkyl substituted phenyl(C₁ -C₃)alkyl, C₁ -C₆monoalkoxy substituted phenyl(C₁ -C₃)alkyl, C₁ -C₆ alkoxy(C₂ -C₄)alkyl,C₅ -C₇ cycloalkyl, C₁ -C₄ monoalkyl substituted C₅ -C₇ cycloalkyl, C₁-C₆ monohaloalkyl, allyl or the group, -C(O)X, wherein X may be C₁ -C₆alkyl, phenyl, C₁ -C₆ mono- or C₁ -C₆ di-alkyl substituted phenyl, C₁-C₆ mono- or C₁ -C₆ di-alkoxy substituted phenyl, C₁ -C₆ alkoxy,phenoxy, C₁ -C₆ mono- or C₁ -C₆ di-alkyl substituted phenoxy, C₁ -C₆mono- or C₁ -C₆ di-alkoxy substituted phenoxy, C₁ -C₆ alkylamino,phenylamino, C₁ -C₆ mono- or C₁ -C₆ di-alkyl substituted phenylamino, orC₁ -C₆ mono- or C₁ -C₆ di-alkoxy substituted phenylamino, said halosubstituent being chloro, fluoro, or bromo. Preferably, R₃ is hydrogen,C₁ -C₃ alkyl, phenyl(C₁ -C₃)alkyl, or the group, -C(O)X, wherein X is aC₁ -C₄ alkyl.

In graphic formula I A, B and B' may each be selected from the groupconsisting of (i) the substituted or unsubstituted aryl groups phenyland naphthyl, (ii) the substituted or unsubstituted heterocyclicaromatic groups pyridyl, furyl, benzofuryl, thienyl, benzothienyl, and(iii) B and B' taken together form the spiro adamantylene group. Thearyl and heterocyclic substituents of B and B' may each be selected fromthe group consisting of hydroxy, C₁ -C₅ alkyl, C₁ -C₅ haloalkyl, C₁ -C₅alkoxy, C₁ -C₅ alkoxy(C₁ -C₄)alkyl, C₁ -C₅ dialkylamino, acryloxy,methacryloxy, and halogen, said halogen or (halo) groups being fluoro,chloro, or bromo, provided that at least one of B and B' is asubstituted or unsubstituted phenyl, except when B and B' form the spiroadamantylene group.

Preferably, B and B' are represented respectively by the followinggraphic formulae: ##STR3## wherein, Y₁ may be selected from the groupconsisting of C₁ -C₅ alkyl, C₁ -C₅ alkoxy, fluoro, and chloro; Z₁ may beselected from the group consisting of hydrogen and Y₁ ; each Y₂ and Z₂are selected from the group consisting of C₁ -C₅ alkyl, C₁ -C₅ alkoxy,hydroxy, halogen, e.g., chloro, fluoro, and bromo, acryloxy, andmethaeryloxy, and a and b are each integers of from 0 to 2. Preferably,Y₁ is C₁ -C₃ alkyl, C₁ -C₃ alkoxy, or fluoro, Z₁ is hydrogen, each Y₂and Z₂ is selected from the group consisting of C₁ -C₃ alkyl and C₁ -C₃alkoxy, a is the integer 0 or 1, and b is an integer from 0 to 2.

The preferred naphthopyrans of the present invention are represented inthe following graphic formula I B, which also shows the numbering of thering atoms: ##STR4## Compounds represented by graphic formula I C areprepared by a coupling reaction followed by derivatizatlon as shown inReaction C. The propargyl alcohol represented by graphic formula VI,which is used in Reaction C, may be prepared by methods described inReaction A and Reaction B. The substituted naphthalene diol, representedby graphic formula VII A, which is used in Reaction C, may be preparedby a method described hereinafter. The substituted naphthol representedby graphic formula VII B, that is used in Reaction E to make thecompounds represented by graphic formula I D may be prepared by themethods described in Reaction D.

Benzophenone compounds represented by graphic formula V shown inReaction A may be purchased from fine chemical manufacturers, customsynthesized or may be prepared by Friedel-Crafts methods using anappropriately substituted or unsubstituted benzoyl chloride of graphicformula IV and a commercially available substituted benzene compound ofgraphic formula III. See the publication, Friedel-Crafts and Related.Reactions, George A. Olah, Interscience Publishers, 1964, Vol. 3,Chapter XXXI (Aromatic Ketone Synthesis).

In Reaction A, the compounds represented by graphic formulae III and IVare dissolved in a solvent, such as carbon disulfide or methylenechloride, and reacted in the presence of a Lewis acid, such as aluminumchloride, to form the corresponding benzophenone represented by graphicformula V. ##STR5##

In Reaction B, the substituted benzophenone represented by graphicformula V is reacted with sodium acetylide in a suitable solvent, suchas dry tetrahydrofuran (THF), to form the corresponding propargylalcohol, which may be represented by graphic formula VI. ##STR6##

In Reaction C, the propargyl alcohol represented by graphic formula VIis coupled with a 7-substituted 2,6-naphthalene diol, represented bygraphic formula VII A, under acidic conditions to form the naphthopyranof graphic formula VIII A. 7-substituted 2,6-naphthalene diol e.g.,2,6-dihydroxy-7-carbomethoxynaphthalene can be prepared by methodsdescribed for the synthesis of n-hexyl-3,7-dihydroxy-2-naphthoatedescribed in the Journal of the American Chemical Society 104, pages7196 to 7204, 1982.

In order to make the compound represented by graphic formula I C, it isnecessary to derivatize, i.e., acylate, methylate, benzylate, etc. . . ., the hydroxyl group on the number 8 carbon atom of the naphthopyranrepresented by graphic formula VIII A. This is accomplished by reactionof the hydroxyl group with an alkyl or aroyl halide, chloroformate,isocyanate, etc. ##STR7##

In Reaction D, the naphthaldehyde or alkyl aryl ketone represented bygraphic formulae IX A and IX B respectively, is reduced using theWolff-Kishner process to yield the compound represented by graphicformula X, which can be selectively brominated to yield thebromonaphthalene compound of graphic formula XI. This compound may besubjected to high pressure copper mediated solvolysis to produce thesubstituted naphthol represented by graphic formula XII followed bydemethylation to produce the substituted naphthol represented by graphicformula VII B. The various compounds prepared in this series ofreactions may be commercially available from fine chemical manufacturersor may be custom synthesized. ##STR8##

In Reaction E, the propargyl alcohol represented by graphic formula VIis coupled with a substituted naphthol of graphic formula VII B underacidic conditions to form the naphthopyran of graphic formula VIII B.The compound represented by graphic formula I D is produced byderivatizing the hydroxyl group on the number 8 carbon atom of thenaphthopyran compound represented by graphic formula VIII B in anidentical manner as previously discussed for Reaction C. If R₃ ismethyl, the compound represented by graphic formula XII in Reaction Dmay be used directly in place of the compound represented by VII B inReaction E. ##STR9##

Compounds represented by graphic formulae I A through I D may be used inthose applications in which organic photochromic substances may beemployed, such as optical lenses, e.g., ophthalmic and plano lenses,face shields, goggles, ski goggles, visors, camera lenses, windows,automotive windshields, aircraft and automotive transparencies, e.g.,T-roofs, sidelights and backlights, plastic films and sheets, textilesand coatings, e.g., coating compositions such as paints, andverification marks on security documents, e.g., documents such asbanknotes, passports and drivers' licenses for which authentication orverification of authenticity may be desired. Naphthopyrans representedby graphic formula I exhibit color changes from colorless to colorsranging from yellow to orange and red.

Examples of contemplated naphthopyrans within the scope of the inventionare the following:

(a) 3,3-diphenyl-8-hydroxy-9-carbopropoxy-3H-naphtho[2,1-b]pyran;

(b)3-(2-fluorophenyl)-3-(4-methoxyphenyl)-8-hydroxy-9-carbopropoxy-3H-naphtho[2,1-b]pyran;

(c)3-(2-fluorophenyl)-3-(4-methoxyphenyl)-8-hydroxy-9-carbomethoxy-3H-naphtho[2,1-b]pyran;

(d)3-(2,4-dimethoxyphenyl)-3-(4-methoxyphenyl)-8-hydroxy-9-carbomethoxy-3H-naphtho[2,1-b]pyran;

(e) 3,3-diphenyl-8-methoxy-9-carbophenoxy-3H-naphtho[2,1-b]pyran;

(f)3-(2-fluorophenyl)-3-(4-methoxyphenyl)-8-methoxy-9-carbophenoxy-3H-naphtho[2,1-b]pyran;

(g)3-(2-fluorophenyl)-3-(4-methoxyphenyl)-8-methoxy-9-carbomethoxy-3H-naphtho[2,1-b]pyran;

(h)3-(2,4-dimethoxyphenyl)-3-(4-methoxyphenyl)-8-acetoxy-9-carbomethoxy-3H-naphtho[2,1-b]pyran;

(i) 3,3-diphenyl-7-methyl-8-methoxy-3H-naphtho[2,1-b]pyran;

(j)3-(2-methoxy,4-acryloxyphenyl)-3-(4-methacryloxy-phenyl)-8-benzyloxy-9-(carbo-1-indolinyl)-3H-naphtho[2,1-b]pyran;

(k)3-(2,4,6-trifluorophenyl)-3-(2,4,6-trimethoxy-1-naphthyl)-8-acetyl-9-carboniloyl-3H-naphtho[2,1-b]pyran;

(l)3-(2-fluorophenyl)-B-(B-methoxy-2-thienyl)-7-m-pentyl-8-benzoyloxy-3H-naphtho[2,1-b]pyran;and

(m)3,3-spiroadamantylene-8-acetoxy-9-carbomethoxy-3H-naphtho[2,1-b]pyran;

Commercially available photoreactive inorganic glass lenses containingsilver halide particles darken to a neutral gray or brown color insunlight. In order to duplicate this color change in a plastic lensusing the organic photochromic naphthopyrans of the present invention,it is contemplated that such naphthopyrans be used in combination withother appropriate complementary organic photochromic materials so thattogether they produce the desired gray or brown color shade when theplastic lens containing such photochromic materials is exposed toultraviolet light. For example, a compound which colors to yellow may beblended with a compound that colors to an appropriate purple to producea brown shade. Similarly, a compound which is orange in its coloredstate will produce a shade of gray when used in conjunction with anappropriate blue coloring compound.

Particularly contemplated classes of complementary organic photochromiccompounds that may be used in combination with the naphthopyrans of thepresent invention include: purple/blue spiro(indoline) benzoxazines,such as those described in U.S. Pat. No. 4,816,584; spiro(indoline)pyridobenzoxazine photochromic compounds, such as those described inU.S. Pat. No. 4,637,698; spiro(indoline) naphthoxazines, such as thosedescribed in U.S. Pat. Nos. 3,562,172, 3,578,602, 4,215,010 and4,342,668; and benzopyrans and naphthopyrans other than those of thepresent invention having a nitrogen-containing substituent on the carbonatom adjacent to the oxygen of the pyran ring, such as those describedin U.S. Pat. No. 4,818,096. All of the aforedescrlbed spirooxazine- andpyran-type organic photochromic compounds are reported to exhibit acolor change of from colorless to purple/blue on exposure to ultravioletlight. The disclosures of said U.S. Patents may be incorporated hereinby reference.

Other contemplated complementary organic photochromic compounds that arereported to exhibit a color change of from colorless to yellow/orangewhen exposed to UV light may be used in combination with thenaphthopyran compounds of the present invention to augment theyellow/orange color of those activated photochromic compounds. Suchcomplementary yellow/orange compounds include: benzopyrans andnaphthopyrans having a spiro adamantylene group in the 2-position of thepyran ring, such as those described in U.S. Pat. No. 4,826,977; andnaphthopyran compounds such as those described in U.S. Pat. No.5,066,818. The disclosures of such U.S. patents also may be incorporatedherein by reference.

The naphthopyran compounds of the present invention may be used inadmixture with or in conjunction with the aforedescribed complementaryor augmenting organic photochromic compounds in amounts and in a ratiosuch that an organic host material to which the mixture of photochromiccompound(s) is applied or in which they are incorporated exhibit asubstantially neutral color when activated with unfiltered sunlight,i.e., as near a neutral gray or brown color as possible given the colorsof the activated photochromic compounds. The relative amounts of thephotochromic compounds used will vary and depend in part upon therelative intensities of the color of the activated species of suchcompounds.

For example, the naphthopyran compounds of the present invention may becombined with one or more of the aforedescribed purple/bluespirooxazine- and/or pyran-type organic photochromic compounds inamounts and in a ratio such that an organic host material to which themixture of compounds is applied or in which they are incorporatedexhibits a near-brown color. Generally, the weight ratio of each of theaforedescribed spirooxazine- and pyran-type compound(s) to thenaphthopyran compound(s) of the present invention will vary from about1:3 to about 3:1, e.g., between about 1:2 or 0.75:1 and about 2:1.

A near neutral gray color exhibits a spectrum that has relatively equalabsorption in the visible range between 400 and 700 nanometers, e.g.,between 440 and 660 nanometers. A near neutral brown color exhibits aspectrum in which the absorption in the 400-550 nanometer range ismoderately larger than in the 550-700 nanometer range. An alternativeway of describing color is in terms of its chromaticity coordinates,which describe the qualities of a color in addition to its luminancefactor, i.e., its chromaticity. In the CIE system, the chromaticitycoordinates are obtained by taking the ratios of the tristimulus valuesto their sum, e.g., x=X/X+Y+Z and y=Y/X+Y+Z. Color as described in theCIE system can be plotted on a chromaticity diagram, usually a plot ofthe chromaticity coordinates x and y. See pages 47-52 of Principles ofColor Technology, by F. W. Billmeyer, Jr. and Max Saltzman, SecondEdition, John Wiley and Sons, N.Y. (1981).

The amount of photochromic substance or composition-containing sameapplied to or incorporated into a host material is not critical providedthat a sufficient amount is used to produce a photochromic effectdiscernible to the naked eye. Generally such amount can be described asa photochromic amount. The particular amount used depends often upon theintensity of color desired upon irradiation thereof and upon the methodused to incorporate or apply the photochromic substances. Typically, themore compound applied or incorporated, the greater is the colorintensity.

Generally, the amount of each photochromic substance incorporated intoor applied to the host material may range from about 0.01 or 0.05 toabout 10 to 20 percent by weight. More typically, the amount ofphotochromic substance(s) incorporated into or applied to the hostmaterial will range from about 0.01 to about 2 weight percent, moreparticularly, from about 0.01 to about 1 weight percent, e.g., fromabout 0.1 or 0.5 to about 1 weight percent, based on the weight of thehost material. Expressed differently, the total amount of photochromicsubstance incorporated into or applied to an optical host material mayrange from about 0.15 to about 0.35 milligrams per square centimeter ofsurface to which the photochromic substance(s) is incorporated orapplied.

Photochromic compounds of the present invention, mixtures of suchcompounds with other photochromic compounds, or compositions containingsame (hereinafter "photochromic substances") may be applied to orincorporated into a host material by various methods described in theart. Such methods include dissolving or dispersing the substance withinthe host material, e.g., inhibition of the photochromic substance intothe host material by immersion of the host material in a hot solution ofthe photochromic substance or by thermal transfer; providing thephotochromic substance as a separate layer between adjacent layers ofthe host material, e.g., as a part of a polymer film; and applying thephotochromic substance as part of a coating placed on the surface of thehost material. The term "inhibition" or "imbibe" is intended to mean andinclude permeation of the photochromic substance alone into the hostmaterial, solvent assisted transfer absorption of the photochromicsubstance into a porous polymer, vapor phase transfer, and other suchtransfer mechanisms. See U.S. Pat. No. 5,066,818 column 14, line 41 tocolumn 15, line 25 for examples of the above methods.

The polymer host material will usually be transparent, but may betranslucent or even opaque. The polymer product need only be transparentto that portion of the electromagnetic spectrum, which activates thephotochromic substance, i.e., that wavelength of ultraviolet (UV) lightthat produces the open form of the substance and that portion of thevisible spectrum that includes the absorption maximum wavelength of thesubstance in its UV activated form, i.e., the open form. Further, theresin color should not be such that it masks the color of the activatedform of the photochromic substance, i.e., so the change in color isreadily apparent to the observer. Preferably, the host material articleis a solid transparent or optically clear material.

Examples of host materials which may be used with the photochromicsubstances or compositions described herein include: polymers, i.e.,homopolymers and copolymers, of polyol(allyl carbonate) monomers, e.g.,diethylene glycol bis(allyl carbonate), polymers, i.e., homopolymers andcopolymers, of polyfunctional acrylate monomers, polyacrylates, whichare polymers of esters of acrylic acid or methacrylic acid, such asmethyl acrylate and methyl methacrylate, cellulose acetate, cellulosetriacetate, cellulose acetate propionate, cellulose acetate butyrate,poly(vinyl acetate), poly(vinyl alcohol), poly(vinyl chloride),poly(vinylidene chloride), polyurethanes, polycarbonates, poly(ethyleneterephthalate), polystyrene, copoly(styrene-methyl methacrylate)copoly(styrene-acrylonitrile), polyvinylbutyral and polymers, i.e.,homopolymers and copolymers, of diallylidene pentaerythritol,particularly copolymers with polyol (allyl carbonate) monomers, e.g.,diethylene glycol bis(allyl carbonate), and acrylate monomers.

Transparent copolymers and blends of the transparent polymers are alsosuitable as host materials. Preferably, the host material is anoptically clear polymerized organic material prepared from apolycarbonate resin, such as the carbonate-linked resin derived frombisphenol A and phosgene, i.e., poly(4,4'-dioxy-diphenol-2,2-propane)carbonate, which is sold under the trademark, LEXAN; a poly(methylmethacrylate), such as the material sold under the trademark, PLEXIGLAS;polymerizates of a polyol(allyl carbonate), especially diethylene glycolbis(allyl carbonate), which monomer is sold under the trademark, CR-39,and polymerizates of copolymers of a polyol (allyl carbonate), e.g.,diethylene glycol bis(allyl carbonate), with other copolymerizablemonomeric materials, such as copolymers with vinyl acetate, e.g.,copolymers of from 80-90 percent diethylene glycol bis(allyl carbonate)and 10-20 percent vinyl acetate, particularly 80-85 percent of thebis(allyl carbonate) and 15-20 percent vinyl acetate, and copolymerswith a polyurethane, e.g., a polyesterurethane, having terminal allyland/or acrylyl functional groups, as described in U.S. Pat. Nos.4,360,653, 4,994,208, and 5,200,483; cellulose acetate, cellulosepropionate, cellulose butyrate, cellulose acetate butyrate, polystyreneand copolymers of styrene with methyl methacrylate, vinyl acetate andacrylonitrile.

Polyol (allyl carbonate) monomers which may be polymerized to form atransparent host material are the allyl carbonates of linear or branchedaliphatic or aromatic liquid polyols, e.g., aliphatic glycol bis(allylcarbonate) compounds, or alkylidene bisphenol bis(allyl carbonate)compounds. These monomers can be described as unsaturated polycarbonatesof polyols, e.g, glycols. The monomers can be prepared by procedureswell known in the art, e.g., U.S. Pat. Nos. 2,370,567 and 2,403,113.

Compatible (chemically and color-wise) tints, i.e., dyes, may be appliedto the host material to achieve a more aesthetic result for medicalreasons or for reasons of fashion. The particular dye selected will varyand depend on the aforesaid need and result to be achieved. In oneembodiment, the dye may be selected to complement the color resultingfrom the activated photochromic substances, e.g., to achieve a moreneutral color or absorb a particular wavelength of incident light. Inanother embodiment, the dye may be selected to provide a desired hue tothe host matrix when the photochromic substance is in an inactivatedstate.

Typically, tinting is accomplished by immersion of the host material ina heated aqueous dispersion of the selected dye. The degree of tint iscontrolled by the temperature of the dye bath and the length of time thehost material is allowed to remain in the bath. Generally, the dye bathis at temperatures of less than 100° C., e.g., from 70° C. to 90° C.,such as 80° C., and the host material remains in the bath for less thanfive (5) minutes, e.g., between about 0.5 and 3 minutes, e.g., about 2minutes. The degree of tint is such that the resulting article exhibitsfrom about 70 to 85 percent, e.g., 80-82 percent, light transmission.

Adjuvant materials may also be incorporated into the host material withthe photochromic substances prior to, simultaneously with or subsequentto application or incorporation of the photochromic substances in thehost material. For example, ultraviolet light absorbers may be admixedwith photochromic substances before their application to the hostmaterial or such absorbers may be superposed, e.g., superimposed, as alayer between the photochromic substance and the incident light.Further, stabilizers may be admixed with the photochromic substancesprior to their application to the host material to improve the lightfatigue resistance of the photochromic substances. Stabilizers, such ashindered amine light stabilizers and singlet oxygen quenchers, e.g., anickel ion complex with an organic ligand, are contemplated. They may beused alone or in combination. Such stabilizers are described in U.S.Pat. No. 4,720,356. Finally, appropriate protective coating(s) may beapplied to the surface of the host material. These may be abrasionresistant coatings and/or coatings that serve as oxygen barriers. Suchcoatings are known in the art.

The present invention is more particularly described in the followingexamples which are intended as illustrative only, since numerousmodifications and variations therein will be apparent to those skilledin the art.

EXAMPLE 1 Step 1

3,7-dihydroxy-2-naphthoic acid (17.4 grams, 0.085 mole) and sodiumbicarbonate (21 grams, 0.25 mole) were suspended with stirring in 120milliliters of dimethylformamide (DMF) in a 500 milliliter round bottomflask equipped with a reflux condenser and nitrogen pad. The mixture waswarmed to 70° C. and held there for 2 hours. Afterwards, the mixture wascooled to room temperature and propyl iodide (16.6 grams, 0.1 mole ) wasadded. The stirred reaction mixture was then gradually warmed to 70° C.where it was kept for 3 hours. Subsequently, the contents of the flaskwere poured into approximately 480 milliliters of ice and water toprecipitate the product. The resulting yellow solid was suction filteredand washed with a sodium bicarbonate solution in order to remove anyunreacted starting material. The yellow solid was next washed with waterand air dried. High-performance liquid chromatographic (HPLC) analysisrevealed that the solid consisted of propyl 3,7-dihydroxy-2-naphthoatecontaining a small amount of propyl 3-hydroxy-2-naphthoate. The yield of3,7-dihydroxy-2-naphthoate was 16.7 grams.

Step 2

Propyl 3,7-dihydroxy-2-naphthoate (3.0 grams, 0.012 mole) from Step 1was added to a reaction flask containing 0.015 mole1,1-diphenyl-2-propyn-1-ol in 100 milliliters of toluene and stirred atroom temperature. A catalytic amount of dodecylbenzene sulfonic acid (anamount sufficient to produce a deep red-brown colored solution) wasadded and the reaction mixture was heated for five hours at 50° C.Afterwards, the reaction mixture was kept at room temperature for about18 hours and then washed twice with water. Toluene was removed undervacuum to yield an oily product. The resultant oil was taken up in 5 to10 milliliters of a 2:1 mixture of hexane:ethyl acetate. Crystals of theproduct formed and were suction filtered and washed with fresh solventuntil no additional color was removed. Occasionally, if the oil solventmixture did not crystallize, the mixture was purified on a silica gelcolumn using a hexane:ethyl acetate mixture as eluant. The photochromicfractions were combined and the remaining eluant was removed undervacuum. The resulting residue was triturated in hexane, suction filteredand dried. A nuclear magnetic resonance (NMR) spectrum showed therecovered product, 2.4 grams, to have a structure consistent with3,3-diphenyl-8-hydroxy-9-carbopropoxy-3H-naphtho[2,1-b]pyran.

EXAMPLE 2

The procedure of Example 1 was followed except that1-(2-fluorophenyl)-1-(4-methoxyphenyl)-2-propyn-1-ol was used in placeof 1,1-diphenyl-2-propyn-1-ol in Step 2. A nuclear magnetic resonance(NMR) spectrum showed the recovered product, 5.0 grams, to have astructure consistent with3-(2-fluorophenyl)-3-(4-methoxy-phenyl)-8-hydroxy-9-carbopropoxy-3H-naphtho[2,1-b]pyran.

EXAMPLE 3

The procedure of Example 1 was followed except that methyl iodide wasused in place of propyl iodide in Step 1 and1-(2-fluorophenyl)-1-(4-methoxyphenyl)-2-propyn-1-ol was used in placeof 1,1-diphenyl-2-propyn-1-ol in Step 2. The recovered product, 3.0grams, had a melting point of 104° to 106° C. A nuclear magneticresonance (NMR) spectrum showed the recovered product to have astructure consistent with3-(2-fluorophenyl)-3-(4-methoxy-phenyl)-8-hydroxy-9-carbomethoxy-3H-naphtho[2,1-b]pyran.

EXAMPLE 4

The procedure of Example 3 was followed except that1-(2,4-dimethoxyphenyl)-1-(4-methoxyphenyl)-2-propyn-1-ol was used inplace of 1-(2-fluorophenyl)-1-(4-methoxyphenyl)-2-propyn-1-ol in Step 2.The recovered product, 3.0 grams, had a melting point of 128° to 130° C.A nuclear magnetic resonance (NMR) spectrum showed the recovered productto have a structure consistent with3-(2,4-dimethoxyphenyl)-3-(4-methoxyphenyl)-8-hydroxy-9-carbomethoxy-3H-naphtho[2,1-b]pyran.

EXAMPLE 5

Two grams of3,3-diphenyl-8-hydroxy-9-carbopropoxy-3H-naphtho[2,1-b]pyran fromExample 1 was added to a reaction flask containing 100 milliliters ofacetone. Two grams each of anhydrous potassium carbonate and dimethylsulfate were added to the reaction flask. The resulting reaction mixturewas stirred and heated for 20 hours at 50° C. under a nitrogenatmosphere. After cooling to room temperature, acetone was removed undervacuum. 25 milliliters each of water and methylene chloride were addedto the mixture, which was then stirred for 15 minutes. The organic phasewas separated and the residual methylene chloride was removed undervacuum. The resulting oil was crystallized from hexane. Crystals of theproduct were suctioned filtered, triturated with fresh hexane, suctionfiltered and dried. The recovered product, 1.3 grams, had a meltingpoint of 127° to 129° C. A nuclear magnetic resonance (NMR) spectrumshowed the recovered product to have a structure consistent with3,3-diphenyl-8-methoxy-9-carbopropoxy-3H-naphtho[2,1-b]pyran.

EXAMPLE 6

The procedure of Example 5 was followed except that3-(2-fluorophenyl)-3-(4-methoxyphenyl)-8-hydroxy-9-carbopropoxy-3H-naphtho[2,1-b]-pyranfrom Example 2 was used in place of3,3-di-phenyl-8-hydroxy-9-carbopropoxy-3H-naphtho[2,1-b]-pyran. Therecovered product, 0.8 grams, had a melting point of 103° to 105° C. Anuclear magnetic resonance (NMR) spectrum showed the recovered productto have a structure consistent with3-(2-fluoro-phenyl)-3-(4-methoxyphenyl)-8-methoxy-9-carbopropoxy-3H-naphtho[2,1-b]pyran.

EXAMPLE 7

The procedure of Example 5 was followed except that3-(2-fluorophenyl)-3-(4-methoxyphenyl)-8-hydroxy-9-carbomethoxy-3H-naphtho[2,1-b]-pyranfrom Example 3 was used in place of 3,3-diphenyl-8-hydroxy-9-carbopropoxy-3H-naphtho[2,1-b]-pyran. The recovered product,1.2 grams, had a melting point of 174° to 176° C. A nuclear magneticresonance (NMR) spectrum showed the recovered product to have astructure consistent with3-(2-fluorophenyl)-3-(4-methoxy-phenyl)-8-methoxy-9-carbomethoxy-3H-naphtho[2,1-b]pyran.

EXAMPLE 8

Three grams of 3-(2,4-dimethoxyphenyl)-3-(4-methoxy-phenyl)-8-hydroxy-9-carbomethoxy-3H-naphtho[2,1-b]-pyranprepared in Example 4 was added to a reaction flask containing 1.5 gramseach of acetic anhydride and triethyl amine in 100 milliliters ofchloroform. The mixture was refluxed under a nitrogen atmosphere for 24hours. The resulting mixture was poured into 50 milliliters of dilutehydrochloric acid, the organic layer was separated, and the solvent,chloroform, was removed under vacuum. About 5 to 10 milliliters of amixture of hexane:ethyl acetate was added to crystallize the productfrom the resulting residue. Crystals of the product were suctionfiltered, washed with fresh solvent until no additional color wasremoved, and then dried. The recovered product, 1.8 grams, had a meltingpoint of 168° to 169° C. A nuclear magnetic resonance (NMR) spectrumshowed the recovered product to have a structure consistent with3-(2,4-dimethoxy-phenyl)-3-(4-methoxyphenyl)-8-acetoxy-9-carbomethoxy-3H-naphtho[2,1-b]pyran.

EXAMPLE 9 Step 1

Ten grams of purchased 5-methyl-6-methoxy-2-bromo-naphthalene was addedto the reaction vessel of a 500 milliliter autoclave, containing 150milliliters of an aqueous solution of potassium hydroxide (15 grams), 30grams of polyethylene glycol monomethyl ether, and one gram of a 50:50mixture of copper bronze and copper powder. The autoclave was sealed andheated to 200° C. while stirring at 1200 revolutions per minute (RPM).After five hours, the autoclave was cooled to room temperature and thecontents were filtered. The aqueous filtrate was acidified with dilutehydrochloric acid and the resulting precipitate was suction filtered.The recovered solid was dissolved in aqueous sodium hydroxide and thesolution filtered. The resulting filtrate was acidified with dilutehydrochloric acid and the resulting precipitate suction filtered anddried. The recovered product, 5.5 grams, had a melting point of 122° to124° C. A nuclear magnetic resonance (NMR) spectrum showed the recoveredproduct to have a structure consistent with5-methyl-6-methoxy-2-naphthol.

Step 2

Two grams of 5-methyl-6-methoxy-2-naphthol, prepared in Step 1, wasadded to a reaction flask containing a molar excess of1,1-diphenyl-2-propyn-1-ol in 150 milliliters of toluene. A catalyticamount of dodecylbenzene sulfonic acid (an amount sufficient to producea dark red-brown colored solution) was added and the reaction mixturewas heated for three hours at 45° C. Afterwards, 100 milliliters ofwater was added and the organic layer was separated. The organic layerwas first washed with dilute aqueous sodium hydroxide and then washedwith water. Toluene was removed under vacuum yielding a pasty solid. Thepasty solid was slurried with a few milliliters of diethyl ether andfiltered. The resulting crystals were washed with diethyl ether until noadditional color was removed and then dried. The recovered product, 1.4grams, had a melting point of 230° to 231.5° C. A nuclear magneticresonance (NMR) spectrum showed the recovered product to have astructure consistent with3,3-diphenyl-7-methyl-8-methoxy-3H-naphtho[2,1-b]pyran.

COMPARATIVE EXAMPLE 1 Step 1

A reaction flask was charged with 200 milliliters of acetone, powderedpotassium carbonate (13.8 grams, 0.1 mole) and 2,6-dihydroxynaphthalene(16.0 grams, 0.1 mole). Dimethylsulfate (12.6 grams, 0.1 mole) was addeddropwise and the reaction mixture was stirred at room temperature for 72hours under a nitrogen atmosphere. Sodium hydroxide (200 milliliters ofa 10% aqueous solution) was then added to the reaction flask. The whiteprecipitate that formed was removed by vacuum filtration. The aqueousfiltrate was acidified with hydrochloric acid to a pH of 3 and theaqueous solution extracted three times with 100 milliliter portions ofmethylene chloride. The extracts were combined, dried over anhydrousmagnesium sulfate for 10 minutes and the solvent removed under vacuum.The residue was washed with hot water and dried to yield 3.0 grams of asolid product, which was confirmed by NMR spectroscopy to be6-methoxy-2-hydroxynaphthalene.

Step 2

6-methoxy-2-hydroxynaphthalene (1.1 grams, 0.006 mole) from Step 1, wasadded to a reaction flask containing 100 milliliters of benzene and1,1-diphenyl-2-propyn-1-ol (1.3 grams, 0.006 mole). A catalytic amount(approximately 20 milligrams) of p-toluene sulfonic acid was added andthe resulting mixture stirred under a nitrogen atmosphere. The reactionmixture was heated gently at 50° C. for 4 hours, cooled, and then 200 mlof a 10% aqueous sodium hydroxide solution was added. After stirring for15 minutes, the reaction mixture was extracted twice with 100 milliliterportions of methylene chloride. The extracts were combined, dried overanhydrous magnesium sulfate and the solvent removed under vacuum. Theproduct (1.0 grams) melted at 173°-175° C. An NMR spectrum showed therecovered product to have a structure consistent with3,3-diphenyl-8-methoxy-3H-naphtho[2,1-b]pyran.

COMPARATIVE EXAMPLE 2

1,1-diphenyl-2-propyn-1-ol (20.8 grams, 0.1 mole) was added to areaction flask containing 200 milliliters of benzene and 15 grams of2-naphthol. The reaction mixture was warmed to 55° C. and after all ofthe 2-naphthol was dissolved, 0.25 grams of p-toluenesulfonic acid wasadded. The mixture changed from light tan to dark black and thetemperature rose to 70° C. After a few minutes, the reaction mixturelightened and began to cool. Thirty minutes later, the contents of theflask were poured into 100 milliliters of 10 percent aqueous sodiumhydroxide and shaken. The organic phase was separated, washed once with10 percent aqueous sodium hydroxide, and then washed with water. Benzenewas removed on a rotary evaporator and the resulting light tan solidresidue was slurried with 100 milliliters of hexane and then filtered.The filtered solid was washed again with 100 milliliters of hexane anddried to provide 18.4 grams of the product, 3,3-diphenyl-3H-naphtho[2,1-b]pyran. The solid product had a melting point of 156°-158° C. andwas 98 percent pure, as determined by liquid chromatographic analysis.

COMPARATIVE EXAMPLE 3 Step 1

A reaction flask was charged with eight grams of2-fluoro-4'-methoxybenzophenone, (prepared by the Friedel-Craftsreaction of 2-fluorobenzoylchloride with anisole), 150 milliliters oftetrahydrofuran, and 14.0 grams of an 18 weight percent slurry of sodiumacetylide in xylene/mineral oil. The reaction mixture was stirred atroom temperature under a nitrogen atmosphere for 72 hours. The contentsof the flask were poured into a 500 milliliter beaker containing icewater and extracted three times with 100 milliliter portions ofmethylene chloride. The extracts were combined, dried over anhydrousmagnesium sulfate and the solvent removed under vacuum. The crudeproduct, 7.0 grams, was isolated as a yellow oil. This oil was shown byNMR to contain the desired product;1-(2-fluorophenyl)-1-(4-methoxyphenyl)-2-propyn-1-ol.

Step 2

1-(2-fluorophenyl)-1-(4-methoxyphenyl)-2-propyn-1-ol (2.4 grams, 0.008mole), as prepared in Step 1, was added to a reaction flask containing100 milliliters of benzene and 6-methoxy-2-hydroxy-naphthalene (1.4grams, 0.008 mole). A catalytic amount of p-toluene sulfonic acid(approximately 20 milligrams) was added and the resulting mixturestirred and heated between 30°-35° C. under a nitrogen atmosphere for 3hours. The reaction mixture was poured into an equal volume of 20%aqueous sodium hydroxide and extracted three times with 100 milliliterportions of methylene chloride. The extracts were combined, dried overanhydrous magnesium sulfate and solvent removed under vacuum. Theresultant oil was column chromatographed on silica using 1:10 mixture ofethyl acetate:hexane as the eluant. The photochromic fractions werecombined, concentrated under vacuum, and crystallized by cooling indiethyl ether. The crystals (0.5 g) were suction filtered and dried. Themelting point of the crystals was 120°-123° C. An NMR spectrum showedthe recovered product to have a structure consistent with3-(2-fluorophenyl)-3-(4-methoxyphenyl)-8-methoxy-BH-naphtho[2,1-b]pyran.

COMPARATIVE EXAMPLE 4 Step 1

1,3-Dimethoxybenzene (13.8 grams, 0.1 mole) and p-anisoyl chloride (17grams, 0.1 mole) were dissolved in 200 milliliters of methylene chlorideand stirred at room temperature. Anhydrous aluminum chloride (15 grams)was added slowly to the reaction mixture over a period of 15 minuteswith stirring. After stirring an additional 15 minutes, the contents ofthe flask were carefully poured into 200 milliliters of a mixture of iceand dilute hydrochloric acid. The organic fraction was separated andwashed with water. The solvent was removed on a rotary evaporatorleaving an oily product that solidified on standing. This solid wasbroken-up, washed with two 50 milliliter portions of pentane, and dried,yielding 2,4,4'-trimethoxybenzophenone.

Step 2

10 grams of 2,4,4'-trimethoxybenzophenone, as prepared in Step 1, wasconverted to the corresponding propargyl alcohol by the proceduredescribed in Step 1 of Comparative Example 3. The resulting crudeproduct was shown by NMR to contain the desired product1-(2,4-dimethoxyphenyl)-1-(4-methoxyphenyl)-2-propyn-1-ol.

Step 3

The crude propargyl alcohol from step 2 was added to a reaction flaskcontaining a slurry of 5 grams of 2-naphthol in 200 milliliters oftoluene. A few drops of dodecyl benzene sulfonic acid (an amountsufficient to turn the mixture a dark red-brown color) were added andthe mixture was warmed to 50° C. for a period of two hours. The reactionmixture was cooled and washed twice with 50 milliliter portions ofwater. The organic fraction was concentrated on a rotary evaporator andthe residue chromatographed on a silica column and eluted with a 2:1mixture of hexane:ethyl acetate. The photochromic fractions werecombined and concentrated under vacuum. The residue was induced tocrystallize by adding a few milliliters (less than 10 milliliters) of ahexane diethyl ether mixture and cooling. The product crystals werewashed with diethyl ether and dried to yield 4 grams of a product havinga melting point of 144°-146° C. A nuclear magnetic resonance (NMR)spectrum showed the solid product to have a structure consistent with3-(2,4-dimethoxyphenyl)-3-(4-methoxyphenyl)-3H-naphtho[2,1-b]pyran.

EXAMPLE 10 Part A

The products of Examples 1, 5, 8, 9, and Comparative Examples 1 and 2were dissolved in diethylene glycol dimethyl ether. The concentrationsof the resulting solutions were approximately 0.5 milligram permilliliter. Each solution was tested in a UV spectrophotometer todetermine its activating wavelength. The activating wavelength reportedin Table 1 is the wavelength at which activation of the photochromiccompound occurs in diethylene glycol dimethyl ether. That valuecorresponds to the absorption peak in the ultraviolet region that isclosest to the visible region or the threshold range, i.e., 390 to 410nanometers, if there is only one absorption peak in this region. Ifthere is more than one absorption peak, the activating wavelengthcorresponds most closely to the absorption peak that immediatelyproceeds the peak of longer wavelength in the ultraviolet region or thethreshold range.

Part B

Further testing was done on naphthopyrans of Example 5 and ComparativeExamples 1 and 2, which were imbibed by thermal transfer into testsquares of a homopolymer of diethylene glycol bis(allyl carbonate) bythe following procedure. Each naphthopyran was dissolved into toluenesolvent to form a 4 weight percent solution of the compound. A piece ofNo. 4 Whatman filter paper was saturated with the naphthopyran solutionand allowed to air dry. The dried filter paper was placed on one side ofthe polymer test square, which measured 1/8 inch (0.3 centimeter)×2 inch(5.1 centimeters)×2 inch (5.1 centimeters). A piece of untreated filterpaper was placed on the other side of the polymer test square and theresulting sandwich placed between two plates of flat aluminum metalplates. The entire assembly was then placed in a 155° C. oven for a timesufficient to thermally transfer the naphthopyran into the polymer testsquare. Residence times in the oven were adjusted to imbibe comparableamounts of the naphthopyran compounds in order to yield a comparable UVabsorbance at their activating wavelength. The imbibed test squares werewashed with acetone after removal from the oven.

The test samples were evaluated for photochromic response rates on anoptical bench. The samples were illuminated by a 150 watt Xenon lampfitted with a copper sulfate bath, a 320 nanometer filter, and a neutraldensity filter at an intensity of about one sun. A second beam of lightprovided by a filtered tungsten lamp arranged to pass through the samplearea exposed by the UV source was used to monitor changes intransmission of the sample over different wavelength ranges in thevisible region of the spectrum. The intensity of the monitoring beamafter passing through the sample was measured by means of an IL-1500radiometer equipped with a silicon detector head and matching filters.

The Δ OD/Min, which represents the sensitivity of the photochromiccompound's response to UV light, was measured using photopic filters onthe silicon detector. The response of the filtered detector approximatedthe luminosity curve. The Δ OD was measured over the first five (5)seconds of UV exposure, then expressed on a per minute basis. Thesaturation optical density (OD) was taken under identical conditions asthe Δ OD/Min, except UV exposure was continued for 20 minutes for theexamples in Table 2. The Bleach Rate T 1/2 is the time interval inseconds for the absorbance of the activated form of the naphthopyran inthe test polymers to reach one half the highest absorbance at roomtemperature (72° F., 22.2° C.) after removal of the source of activatinglight. Results are tabulated in Table 2.

Part C

The solar response for naphthopyrans of Example 7 and ComparativeExamples 3 and 4 was measured using the optical bench described in PartB. The naphthopyrans were imbibed by thermal transfer into test squaresof a polymeric matrix prepared from a diethylene glycol bis(allylcarbonate) composition and two optical density measurements were madeafter 15 minute exposures to a UV source first fitted with a 320nanometer filter and then fitted with a 360 nanometer filter. The lossin response was calculated by subtracting the optical density obtainedwith the 360 nanometer filter from the optical density obtained with the320 nanometer filter and then dividing this figure by the opticaldensity obtained with the 320 nanometer filter and multiplying by 100.

The loss in response measurement, expressed as a percent, simulates thedifference between the photochromic response of the compounds exposed tofull mid-day sun and to low light conditions, such as early day and latein the day when the lower wavelength components of the UV spectrum areattenuated. The results for the loss in response, activating wavelength,and the Bleach Rate T 1/2 are listed in Table 3.

                  TABLE 1                                                         ______________________________________                                        Activating Wavelength in                                                      Diethylene Glycol Dimethyl Ether                                                            ACTIVATING                                                                    WAVELENGTH                                                      ______________________________________                                        COMPOUND                                                                      EXAMPLE                                                                       1               408                                                           5               382                                                           8               376                                                           9               369                                                           COMPARATIVE                                                                   EXAMPLE                                                                       1               359                                                           2               348                                                           ______________________________________                                    

                  TABLE 2                                                         ______________________________________                                               Δ OD/Min                                                                SENSI-  Δ OD @ BLEACH RATE                                              TIVITY  SATURATION   T 1/2 (SEC.)                                      ______________________________________                                        COM-     1.4       0.55         80                                            POUND                                                                         EXAMPLE                                                                       COMPARA-                                                                      TIVE                                                                          EXAMPLE                                                                       1        1.25      0.73         87                                            2        0.87      0.36         45                                            ______________________________________                                    

                                      TABLE 3                                     __________________________________________________________________________              Δ OD @                                                                       Δ OD @                                                                       % LOSS IN                                                                            ACTIVATING                                                                             BLEACH RATE                                         320 nm                                                                             360 nm                                                                             RESPONSE                                                                             WAVELENGTH                                                                             T 1/2 (SEC.)                              __________________________________________________________________________    COMPOUND  0.187                                                                              0.184                                                                              2%     384      196                                       EXAMPLE                                                                       COMPARATIVE                                                                   EXAMPLE                                                                       3         0.266                                                                              0.249                                                                              6%     359      356                                       4         0.260                                                                              0.196                                                                              25%    348      338                                       __________________________________________________________________________

The results in Table 1 demonstrate the unexpectedly higher activatingwavelength of the compounds of the present inventions, vis-a-vis,comparative example 1, which has a methoxy substituent at the number 8carbon atom, and comparative example 2, which has no substituents on thenaphthalene nucleus. Table 2 shows that the compound of example 5 has anincreased sensitivity as compared to the compounds of comparativeexamples 1 and 2. The results in Table 3reveal less reduction in opticaldensity measured after exposure to a xenon light with a 360 nm cutofffilter as compared to the optical density measured after exposure to thesame light source and a 320 nm cutoff filter, for compound example 7 ascompared to comparative examples 3 and 4. Also, Table 3 shows that thecompound of example 7 has a more acceptable Bleach Rate T 1/2, i.e.,rate of fade.

Although the present invention has been described with reference to thespecific details of particular embodiments thereof, it is not intendedthat such details be regarded as limitations upon the scope of theinvention except insofar as and to the extent that they are included inthe accompanying claims.

What is claimed is:
 1. A naphthopyran compound represented by thefollowing graphic formula: ##STR10## wherein: (a) R1 is hydrogen or a C₁-C₆ alkyl; R₂ is hydrogen or the group, -C(O)W, W being -OR₄ or-N(R₅)R₆, wherein R₄ is hydrogen, allyl, C₁ -C₆ alkyl, phenyl, C₁ -C₆monoalkyl substituted phenyl, C₁ -C₆ monoalkoxy substituted phenyl,phenyl(C₁ -C₃)alkyl, C₁ -C₆ monoalkyl substituted phenyl(C₁ -C₃)alkyl,C₁ -C₆ monoalkoxy substituted phenyl(C₁ -C₃)alkyl, C₁ -C₆ alkoxy(C₂-C₄)alkyl, or C₁ -C₆ monohaloalkyl, and wherein R₅ and R₆ are eachselected from the group consisting of hydrogen, C₁ -C₆ alkyl, C₅ -C₇cycloalkyl, phenyl and mono- or di-substituted phenyl, or R₅ and R₆together with the nitrogen form a mono- or di-substituted orunsubstituted heterocyclic group selected from the group consisting ofindolinyl, morpholino, piperidino, 1-pyrrolidyl, 1-pyrrolinyl,1-imidazolidyl, 2-imidazolin-1-yl, 2-pyrazolidyl, and 1-piperazinyl,said phenyl and heterocyclic ring substituents being selected from C₁-C₆ alkyl and C₁ -C₆ alkoxy and said halo substituent being chloro orfluoro; R₃ is hydrogen, C₁ -C₆ alkyl, phenyl(C₁ -C₃)alkyl, C₁ -C₆monoalkyl substituted phenyl(C₁ -C₃)alkyl, C₁ -C₆ monoalkoxy substitutedphenyl(C₁ -C₃)alkyl, C₁ -C₆ alkoxy(C₂ -C₄)alkyl, C₅ -C₇ cycloalkyl, C₁-C₄ monoalkyl substituted C₅ -C₇ cycloalkyl, C₁ -C₆ monohaloalkyl, allylor the group, -C(O)X, wherein X is a C₁ -C₆ alkyl, phenyl, C₁ -C₆mono-or C₁ -C₆ di-alkyl substituted phenyl, C₁ -C₆ mono- or C₁ -C₆di-alkoxy substituted phenyl, C₁ -C₆ alkoxy, phenoxy, C₁ -C₆ mono- or C₁-C₆ di-alkyl substituted phenoxy, C₁ -C₆ mono- or C₁ -C₆ di-alkoxysubstituted phenoxy, C₁ -C₆ alkylamino, phenylamino, C₁ -C₆ mono- or C₁-C₆ di-alkyl substituted phenylamino, or C₁ -C₆ mono- or C₁ -C₆di-alkoxy substituted phenylamino, and said halo substituent beingchloro, fluoro or bromo, provided that one of R₁ and R₂ is hydrogen;and(b) B and B' are each selected from the group consisting of thesubstituted or unsubstituted aryl groups phenyl and naphthyl, said arylsubstituents being selected from the group consisting of hydroxy, C₁ -C₅alkyl, C₁ -C₅ haloalkyl, C₁ -C₅ alkoxy, C₁ -C₅ alkoxy(C₁ -C₄)alkyl, C₁-C₅ dialkylamino, acryloxy, methacryloxy, and halogen, said halogen or(halo) groups being fluoros chloro, or bromo, provided that at least oneof B and B' is a substituted or unsubstituted phenyl.
 2. Thenaphthopyran of claim 1 wherein B and B' are represented respectively bythe following graphic formulae: ##STR11## wherein, Y₁ is selected fromthe group consisting of C₁ -C₅ alkyl, C₁ -C₅ alkoxy, fluoro, and chloro,Z₁ is selected from the group consisting of hydrogen and Y₁ each Y₂ andZ₂ are selected from the group consisting of C₁ -C₅ alkyl, C₁ -C₅alkoxy, hydroxy, halogen, acryloxy, and methacryloxy, and a and b areeach integers of from 0 to
 2. 3. The naphthopyran of claim 2 wherein R₁is hydrogen or methyl; R₂ is hydrogen or the group, -C(O)W, W being-OR₄, wherein R₄ is C₁ -C₃ alkyl or allyl; and R₃ is hydrogen, C₁ -C₃alkyl, phenyl(C₁ -C₃)alkyl, or the group, -C(O)X wherein X is a C₁ -C₄alkyl.
 4. The naphthopyran of claim 3 wherein Y₁ is C₁ -C₃ alkyl, C₁ -C₃alkoxy, or fluoro, Z₁ is a hydrogen, each Y₂ and Z₂ is selected from thegroup consisting of C₁ -C₃ alkyl and C₁ -C₃ alkoxy, a is the integer 0or 1, and b is an integer from 0 to
 2. 5. A naphthopyran compoundselected from the group consisting of:(a)3,3-diphenyl-8-hydroxy-9-carbopropoxy-3H-naphtho[2,1-b]pyran; (b)3,3-diphenyl-8-methoxy-9-carbophenoxy-3H-naphtho[2,1-b]pyran; (c)3(2-fluorophenyl)-3-(4-methoxyphenyl)-8-methoxy-9-carbopropoxy-3H-naphtho[2,1-b]pyran;(d)3(2-fluorophenyl)-3-(4-methoxyphenyl)-8-methoxy-9-carbomethoxy-3H-naphtho[2,1-b]pyran;(e)3-(2,4-dimethoxyphenyl)-3-(4-methoxyphenyl)-8-acetoxy-9-carbomethoxy-3H-naphtho[2,1-b]pyran;and (f) 3,3-diphenyl-7-methyl-8-methoxy-3H-naphtho[2,1-b]pyran.
 6. Aphotochromic article comprising an organic host material and aphotochromic amount of a naphthopyran compound represented by thefollowing graphic formula: ##STR12## wherein: (a) R₁ is hydrogen or a C₁-C₆ alkyl; R₂ is hydrogen or the group, -C(O)W, W being -OR₄ or-N(R₅)R₆, wherein R₄ is hydrogen, allyl, C₁ -C₆ alkyl, phenyl, C₁ -C₆monoalkyl substituted phenyl, C₁ -C₆ monoalkoxy substituted phenyl,phenyl(C₁ -C₃)alkyl, C₁ -C₆ monoalkyl substituted phenyl(C₁ -C₃)alkyl,C₁ -C₆ monoalkoxy substituted phenyl(C₁ -C₃)alkyl, C₁ -C₆ alkoxy(C₂-C₄)alkyl, or C₁ -C₆ monohaloalkyl, and wherein R₅ and R₆ are eachselected from the group consisting of hydrogen, C₁ -C₆ alkyl, C₅ -C₇cycloalkyl, phenyl and mono- or di-substituted phenyl, or R₅ and R₆together with the nitrogen form a mono- or di-substituted orunsubstituted heterocyclic group selected from the group consisting ofindolinyl, morpholino, piperidino, 1-pyrrolidyl, 1-pyrrolinyl,1-imidazolidyl, 2-imidazolin-1-yl, 2-pyrazolidyl, and 1-piperazinyl,said phenyl and heterocyclic ring substituents being selected from C₁-C₆ alkyl and C₁ -C₆ alkoxy and said halo substituent being chloro orfluoro; R₃ is hydrogen, C₁ -C₆ alkyl, phenyl(C₁ -C₃)alkyl, C₁ -C₆monoalkyl substituted phenyl(C₁ -C₃)alkyl, C₁ -C₆ monoalkoxy substitutedphenyl(C₁ -C₃)alkyl, C₁ -C₆ alkoxy(C₂ -C₄)alkyl, C₅ -C₇ cycloalkyl, C₁-C₄ monoalkyl substituted C₅ -C₇ cycloalkyl, C₁ -C₆ monohaloalkyl, allylor the group, -C(O)X, wherein X is a C₁ -C₆ alkyl, phenyl, C₁ -C₆mono-or C₁ -C₆ di-alkyl substituted phenyl, C₁ -C₆ mono- or C₁ -C₆di-alkoxy substituted phenyl, C₁ -C₆ alkoxy, phenoxy, C₁ -C₆ mono- orC₁ - C₆ di-alkyl substituted phenoxy, C₁ -C₆ mono- or C₁ -C₆ di-alkoxysubstituted phenoxy, C₁ -C₆ alkylamino, phenylamino, C₁ -C₆ mono- or C₁-C₆ di-alkyl substituted phenylamino, or C₁ -C₆ mono- or C₁ -C₆di-alkoxy substituted phenylamino, and said halo substituent beingchloro, fluoro or bromo, provided that one of R₁ and R₂ is hydrogen;and(b) B and B' are each selected from the group consisting of thesubstituted or unsubstituted aryl groups phenyl and naphthyl, said arylsubstituents being selected from the group consisting of hydroxy, C₁ -C₅alkyl, C₁ -C₅ haloalkyl, C₁ -C₅ alkoxy, C₁ -C₅ alkoxy(C₁ -C₄)alkyl, C₁-C₅ dialkylamino, acryloxy, methacryloxy, and halogen, said halogen or(halo) groups being fluoro, chloro, or bromo, provided that at least oneof B and B' is a substituted or unsubstituted phenyl.
 7. Thephotochromic article of claim 6 wherein the organic host material isselected from the group consisting of polyacrylates, cellulose acetate,cellulose triacetate, cellulose acetate propionate, cellulose acetatebutyrate, poly(vinyl acetate), poly(vinyl alcohol), poly(vinylchloride), poly(vinylidene chloride), polycarbonate, polyurethanes,poly(ethylene terephthalate), polystyrene,copoly(styrene-methylmethacrylate), copoly(styrene-acrylonitrile,polyvinylbutyral and polymers of members of the group consisting ofpolyol(allyl carbonate) monomers, polyfunctional acrylate monomers, anddiallylidene pentaerythritol monomers.
 8. The photochromic article ofclaim 7 wherein B and B' are represented respectively by the followinggraphic formulae: ##STR13## wherein, Y₁ is selected from the groupconsisting of C₁ -C₅ alkyl, C₁ -C₅ alkoxy, fluoro, and chloro, Z₁ isselected from the group consisting of hydrogen and Y₁, each Y₂ and Z₂are selected from the group consisting of C₁ -C₅ alkyl, C₁ -C₅ alkoxy,hydroxy, halogen, acryloxy, and methacryloxy, and a and b are eachintegers from 0 to
 2. 9. The photochromic article of claim 8 wherein R₁is hydrogen or methyl; R₂ is hydrogen or the group, -C(O)W, W being-OR₄, wherein R₄ is C₁ -C₃ alkyl or allyl; and R₃ is hydrogen, C₁ -C₃alkyl, phenyl(C₁ -C₃)alkyl, or the group, -C(O)X wherein X is a C₁ -C₄alkyl.
 10. The photochromic article of claim 9 wherein Y₁ is C₁ -C₃alkyl, C₁ -C₃ alkoxy, or fluoro, Z₁ is a hydrogen, each Y₂ and Z₂ isselected from the group consisting of C₁ -C₃ alkyl and C₁ -C₃ alkoxy, ais the integer 0 or 1, and b is an integer from 0 to
 2. 11. Thephotochromic article of claim 10 wherein the organic host material is asolid transparent homopolymer or copolymer of diethylene glycolbis(allyl carbonate), poly(4,4'-dioxydiphenol-2,2-propane) carbonate,poly(methyl-methacrylate), polyvinylbutyral or a polyurethane.
 12. Thephotochromic article of claim 11 wherein the photochromic compound ispresent in an amount of from about 0.15 to 0.35 milligrams per squarecentimeter of organic host material surface to which the photochromiccompound is incorporated or applied.
 13. The photochromic article ofclaim 12 wherein the article is a lens.
 14. A photochromic articlecomprising a solid transparent polymerized organic host material and aphotochromic amount of each of (a) a first photochromic substanceselected from the group consisting of spiro(indoline) naphthoxazines,spiro(indoline) pyridobenzoxazines, spiro(indoline) benzoxazines, andbenzopyrans or naphthopyrans other than the photochromic substance of(b) having a nitrogen-containing substituent on the carbon atom adjacentto the oxygen of the pyran ring, and (b) a second photochromic substanceselected from naphthopyran compounds represented by the followinggraphic formula: ##STR14## wherein: (a) R₁ is hydrogen or a C₁ -C₆alkyl; R₂ is hydrogen or the group, -C(O)W, W being -OR₄ or -N(R₅)R₆,wherein R₄ is hydrogen, allyl, C₁ -C₆ alkyl, phenyl, C₁ -C₆ monoalkylsubstituted phenyl, C₁ -C₆ monoalkoxy substituted phenyl, phenyl(C₁-C₃)alkyl, C₁ -C₆ monoalkyl substituted phenyl(C₁ -C₃)alkyl, C₁ -C₆monoalkoxy substituted phenyl(C₁ -C₃)alkyl, C₁ -C₆ alkoxy(C₂ -C₄)alkyl,or C₁ -C₆ monohaloalkyl, and wherein R₅ and R₆ are each selected fromthe group consisting of hydrogen, C₁ -C₆ alkyl, C₅ -C₇ cycloalkyl,phenyl and mono- or di-substituted phenyl, or R₅ and R₆ together withthe nitrogen form a mono- or di-substituted or unsubstitutedheterocyclic group selected from the group consisting of indolinyl,morpholino, piperidino, 1-pyrrolidyl, 1-pyrrolinyl, 1-imidazolidyl,2-imidazolin-1-yl, 2-pyrazolidyl, and 1-piperazinyl, said phenyl andheterocyclic ring substituents being selected from C₁ -C₆ alkyl and C₁-C₆ alkoxy and said halo substituent being chloro or fluoro; R₃ ishydrogen, C₁ -C₆ alkyl, phenyl(C₁ -C₃)alkyl, C₁ -C₆ monoalkylsubstituted phenyl(C₁ -C₃)alkyl, C₁ -C₆ monoalkoxy substituted phenyl(C₁-C₃)alkyl, C₁ -C₆ alkoxy(C₂ -C₄)alkyl, C₅ -C₇ cycloalkyl, C₁ -C₄monoalkyl substituted C₅ -C₇ cycloalkyl, C₁ -C₆ monohaloalkyl, allyl orthe group, -C(O)X, wherein X is a C₁ -C₆ alkyl, phenyl, C₁ -C₆ mono-orC₁ -C₆ di-alkyl substituted phenyl, C₁ -C₆ mono- or C₁ -C₆ di-alkoxysubstituted phenyl, C₁ -C₆ alkoxy, phenoxy, C₁ -C₆ mono- or C₁ - C₆di-alkyl substituted phenoxy, C₁ -C₆ mono- or C₁ -C₆ di-alkoxysubstituted phenoxy, C₁ -C₆ alkylamino, phenylamino, C₁ -C₆ mono- or C₁-C₆ di-alkyl substituted phenylamino, or C₁ -C₆ mono- or C₁ -C₆di-alkoxy substituted phenylamino and said halo substituent beingchloro, fluoro or bromo, provided that one of R₁ and R₂ is hydrogen;and(b) B and B' are each selected from the group consisting of thesubstituted or unsubstituted aryl groups phenyl and naphthyl, said arylsubstituents being selected from the group consisting of hydroxy, C₁ -C₅alkyl, C₁ -C₅ haloalkyl, C₁ -C₅ alkoxy, C₁ -C₅ alkoxy(C₁ -C₄)alkyl, C₁-C₅ dialkylamino, acryloxy, methacryloxy, and halogen, said halogen or(halo) groups being fluoro, chloro, or bromo, provided that at least oneof B and B' is a substituted or unsubstituted phenyl.
 15. Thephotochromic article of claim 14 wherein the organic host material isselected from the group consisting of polyacrylates, cellulose acetate,cellulose triacetate, cellulose acetate propionate, cellulose acetatebutyrate, poly(vinyl acetate), poly(vinyl alcohol), poly(vinylchloride), poly(vinylidene chloride), polycarbonate, polyurethanes,poly(ethylene terephthalate), polystyrene,copoly(styrene-methylmethacrylate), copoly(styrene-acrylonitrile,polyvinylbutyral and polymers of members of the group consisting ofpolyol(allyl carbonate) monomers, polyfunctional acrylate monomers, anddiallylidene pentaerythritol monomers.
 16. The photochromic article ofclaim 15 wherein B and B' are represented respectively by the followinggraphic formulae: ##STR15## wherein, Y₁ is selected from the groupconsisting of C₁ -C₅ alkyl, C₁ -C₅ alkoxy, fluoro, and chloro, Z₁ isselected from the group consisting of hydrogen and Y₁, each Y₂ and Z₂are selected from the group consisting of C₁ -C₅ alkyl, C₁ -C₅ alkoxy,hydroxy, halogen, acryloxy, and methacryloxy, and a and b are eachintegers of from 0 to
 2. 17. The photochromic article of claim 16wherein R₁ is hydrogen or methyl; R₂ is hydrogen or the group, -C(O)W, Wbeing -OR₄, wherein R₄ is C₁ -C₃ alkyl or allyl; and R₃ is hydrogen, C₁-C₃ alkyl, phenyl(C₁ -C₃)alkyl, or the group, -C(O)X wherein X is a C₁-C₄ alkyl.
 18. The photochromic article of claim 17 wherein Y₁ is C₁ -C₃alkyl, C₁ -C₃ alkoxy, or fluoro, Z₁ is a hydrogen, each Y₂ and Z₂ isselected from the group consisting of C₁ -C₃ alkyl and C₁ -C₃ alkoxy, ais the integer 0 or 1, and b is an integer from 0 to
 2. 19. Thephotochromic article of claim 18 wherein the organic host material is asolid transparent homopolymer or copolymer of diethylene glycolbis(allyl carbonate), poly(4,4'-dioxydiphenol-2,2-propane) carbonate,poly(methylmethacrylate), polyvinylbutyral or a polyurethane.
 20. Thephotochromic article of claim 19 wherein the photochromic compound ispresent in an amount of from about 0.15 to 0.35 milligrams per squarecentimeter of organic host material surface to which the photochromiccompound is incorporated or applied.
 21. The photochromic article ofclaim 20 wherein the weight ratios of the first photochromic substanceto the second photochromic substance is from about 1:3 to about 3:1. 22.The photochromic article of claim 21 wherein the article is anophthalmic lens.